Question

In a quadrilateral $ABCD$, $\angle A+\angle D=180º$. What special name can be given to this quadrilateral?

Answer 1

Explanation:

It is given that $ABCD$ is a quadrilateral and $\angle A+\angle D=180º$.

Therefore, by angle sum property, $\angle B+\angle C=360°-180º=180°$

Since, the sum of co-interior angles of the quadrilateral is $180°$.

This means that it is a trapezium because in a trapezium sum of co-interior angles is $180°$.

Hence, $ABCD$ can be named a Trapezium.